For the Bookshelf I used reference 1 to create the design of the shelvings. By bookshelf was a bit bigger than the reference image so I had to work with this and implement the design into something a bit bigger. Also, the idea of my bookshelf was that it had a balcony and kind of a second-floor idea. So I had to create a duplicate that would go on top of each other.
Then When I came to the part of the balcony I used the same elements of the Spiral staircase a a rail of the balcony. This way when I implemented the spiral staircase these two elements would go nicely with each other. I also extended the handheld rail to be a part of the balcony rails. And lastly, I made a few book stacks as ideas to implement in the bookcase. With these books, I would still have to play around for a bit so that the whole bookshelf would be filled with books. For the texture of the books, I will probably use maybe 2 or 3 different book textures and then play around with the colors of all the different books to really give it that filled-up look.